Files

Data in files is organized as a collection of records. (See Figure 1.) A record is a grouping of related information that has a predefined size and a predefined number and layout of fields. Each record in a file has the same number and layout of fields, which hold specific parts of the record's information. For example, each record can contain information about a bank account, with fields for the account number, name, balance, and other information. The way the records in a file are arranged is called the file organization. For more details, see File organization.

A file has one primary index, which defines the physical sequence of records in the file. A file can also have any number of secondary indexes that provide alternative sequences in which the file's records can be accessed. An index can be seen as a list of pointers to records in a file, where the primary index lists the actual sequence of the records, and each secondary index lists the pointers in a different sequence. Application programs can read, update, add, delete, and browse data in local or remote files. For more details, see Primary and alternate indexes.

CICS® TX on Cloud file services that SFS provides are like those that the Virtual Storage Access Method (VSAM) data sets provide. If you are migrating to CICS TX on Cloud from an IBM® mainframe-based CICS operating system, your application programs can use the same file access commands as used for VSAM data sets.

Figure 1. General file services

For information about adding files to SFS, see How to add files to a Structured File Server (SFS).